Electrohydraulic valves are generally used in hydraulic systems to regulate a flow of a fluid based on electric signals provided by a controller. Electrohydraulic valves may perform various functions within the hydraulic systems, for example, supplying a pressurized fluid to a hydraulic actuator, drain the fluid to a tank, regulate fluid pressure, and so on.
Such electrohydraulic valves generally involve various design and manufacturing complexities. Various moving components of the electrohydraulic valves may also experience wear due to prolonged use. Therefore, responses of the electrohydraulic valves to electrical signals may be unreliable. Hence, calibration of the electrohydraulic valve may be necessary to ensure that the electrohydraulic valves meet desired performance requirements. Calibration of electrohydraulic valves that are fluidly connected with a bypass valve is known in the art. However, there may be a situation in which the hydraulic system may not include a bypass valve.
U.S. Pat. No. 7,562,554 discloses a method for calibrating an independent metering valve. The method for calibrating the independent metering valve having a valve element movable between a flow blocking position and a flow passing position includes directing pressurized fluid to the valve and increasing a current directed to the valve for controlling a position of the valve element. The method further includes sensing a pressure of the fluid. The method for calibrating the valve also includes determining if a time-derivative of the sensed fluid pressure is greater than a predetermined threshold over a predetermined period of time and determining a cracking point current command directed to the valve. The cracking point current command is directed to the valve when the time-derivative of the sensed fluid pressure is greater than the predetermined threshold.